If Mormonism is able to endure, unmodified, until it reaches the third and fourth generation, it is destined to become the greatest power the world has ever known.

This quote originates in Thomas J. Yates, "Count Tolstoi and the 'American Religion' ", Improvement Era (February 1939): 94. According to Yates, American diplomat Andrew Dickson White told him (Yates) in an interview that Tolstoy said this to him (White) during a visit to the Tolstoy estate.

However, according to Leland A. Feltzer, "Tolstoy and Mormonism", Dialogue 6, no. 1 (Spring 1971): 13–29, DOI:10.2307/45227501, Yate likely misremembered the interview. No other contemporaneous evidence corroborates the claim that White visited Tolstoy's estate, and Tolstoy was suspicious of organized religion, making this compliment improbable.